In related art, piezoelectric thin film devices are used for oscillators, filters, and the like. For example, a piezoelectric thin film device illustrated in FIG. 24 is disclosed in Patent Document 1 mentioned below. A piezoelectric thin film device 1001 has a piezoelectric thin film 1002. It is described in Patent Document 1 that the piezoelectric thin film 1002 is desirably made of piezoelectric monocrystal, such as quartz crystal, LiTaO3, or LiNbO3. Electrodes 1003 and 1004 are formed on the upper surface of the piezoelectric thin film 1002. Electrodes 1005 to 1007 are formed on the lower surface of the piezoelectric thin film 1002. By using the electrodes 1003 to 1007, four piezoelectric thin film resonators that utilize thickness shear mode are formed in the piezoelectric thin film device 1001.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-228356